When photocopies were first used after the development and invention of xerography by Chester Carlson, generally a flat photosensitive surface was uniformly charged, exposed to an image, and developed by a developer or a toner. The toner was usually sprinkled across the photosensitive surface so that it would adhere in imagewise configuration and then transferred to a paper surface where it was fused to the paper as a fixed image. In those days, toner was housed in a toner housing having a volume capacity depending on the size of the copier machine. For example, the larger copier machines usually had larger toner bins while desk top smaller copiers had smaller toner bins.
Today, as some copiers are made smaller and more compact, there is a need for using toner cartridges containing toner as dense in total volume as practical, and with a small cartridge. The small cartridge allows less space to be occupied in a small copier, the densely packed toner permits as much usable toner available within this smaller cartridge.
It is, therefore, important to have available a system for filling a cartridge with as much toner as practical and yet not interfere with the flowing properties of the toner during use in a photocopier. One method used to allow the toner cartridge to be filled to a higher density is to remove air from a toner mass during the filling of the cartridge with toner. Evacuating air from a toner mass by the use of a vacuum is a very effective means. By increasing the bulk density of the toners, it is possible to reduce the size of the toner cartridge. Also, packing as much toner in a given size cartridge provides a way to extend the useful life of the cartridge being used and lengthening the time between replacing the toner cartridge with a new fresh cartridge.
In U.S. Pat. No. 5,727,607 (Ichikawa) there is provided a means for suctioning air from the toner during the filling of a container. A section rod adjacent to the toner feed apparatus is inserted into a container through an opening in the container. This suction rod has an end connected to a suction pump while the other end of the rod is provided with a mesh filter that allows suction of the air from the toner accumulated in the container. In the Ichikawa filling process, the opening in the container through which the section rod is inserted provides a means to use a deaerating device to remove air from a toner mass. Ichikawa, in an augerless toner filling system, uses a porous aerating insert to enable the toner movement (flow) from the funnel at the bottom of the toner hopper into the cartridge being filled. This process over aerates the toner deistically increasing its volume. To densify the toner inside the cartridge, an air evacuation element (a suction rod) is inserted through a second opening (in addition to the toner filling opening), and this air evacuation system needs to be airtight for the air removal to work. Also, it is required in Ichikawa to have a filter between the vacuum or suction rod and the source of vacuum to separate the entrained toner particles.
In U.S. Pat. No. 6,497,259 (Wegman), an apparatus is provided for moving powder from a hopper containing a supply of powder to fill a container. The apparatus includes (a) a conduit member operably connected to the hopper and having a discharging end for permitting a powder to be moved therethrough; (b) a nozzle member for directing the powder from the conveyor to fill the container, the nozzle member being operably connected to the discharge end of the conduit member and having a first end connected to the conduit member, and a second and opposite end for dispensing moving powder into the container, and (c) a conveyor device located at least partially within the conduit member for moving the powder from the hopper in a powder-moving direction to the nozzle member, the conveyor device being stoppable for halting the flow of powder, and including a porous portion and vacuum device for additionally halting the flow of powder for a clean shutoff. In Wegman, a porous tip is connected to the end of an auger and by the vacuum supplied through the hollow auger creates a vacuum field compacting the toner or powder in this area, thus creating a plug that stops the toner flow (dribbling) when the auger is not rotating between the filling cycles.